The instant invention relates to a singulating feeder for feeding sheets of paper seriatim from an upstream supply to downstream apparatus and further processing. More particularly, the invention relates to the separating stone used in such a feeder to effect singulation and apparatus which enables the stone to be pivoted away from the paper path and allow jam clearance adjacent the separator stone.
Mechanisms for the feeding of paper documents generally fall into two categories, those being vacuum fed and friction fed. The following description of the prior art will deal only with those types of feeders and material handlers which are considered to be friction-type feeders and which include singulators.
Friction feeders are preferred when it comes to feeding single paper documents. Friction feeders, as the name implies, rely on the interaction of several components that result in the singulation of paper documents. Two methods of singulation are provided by friction feeders. One style is via top feed and the second style is via bottom feed. A friction feeder is designed to operate as a top feed or a bottom feed, but it cannot operate in both modes. The components are usually a drive roller and a retarding device. The retarding device is of a material which provides a high coefficient of friction between the paper being fed and the drive roller.
In a bottom feed configuration, the paper begins as a vertical stack placed on a plurality of belts which usually are supported by a feeder table. This plurality of belts then advance the stack of paper toward a retarding device. As the plurality of belts advance the stack of paper under the retarding device, the friction between the belts and the bottom of the stack of paper tends to pull paper off the bottom of the stack. The retarding device provides the friction that acts to hold back the stack of paper. Therefore, the number of paper documents that are pulled from the bottom of the vertical stack is determined by the physical distance between the belts and the retarding device. If the distance is substantially the thickness of a single piece of paper, or the thickness of the material being singulated, a single paper will be delivered form the bottom of the stack. The single sheet delivery is generally the desired result. If the distance between the belts and the retarding device is the thickness of several pieces of paper or of the documents to be singulated, than a stream of paper documents will be delivered from the stack.
The typical retarding device in a bottom feed configuration is a stationary stone. If a jam should occur under the stone, the only means of clearing the jam is for the operation of the feeder to manually rotate the feeding rollers in order to back the jammed paper away from the stone. Such a task is tedious and time consuming. Because the gap between the feed rollers and the stone is only about 1/1000 inch, it is a very fine adjustment to re-set this gap, and thus all prior art separating stones are fixedly secured. The instant invention provides a pivoting separator stone which can be reliably separated from the paper path and replaced in its original position so that the gap between the stone and the roller is reliably re-set. Thus, an operator is enabled to move a singulating stone away from the path of the paper feed and facilitate quick jam clearance without the need for any feed rollers to be rotated or clearance gaps re-set.